Flexible tubing fastener



Dec. 7,1943;

H. A. PORTER 2,335,883

FLEXIBLE TUBING FASTENER Filed Oct. '7, 1941 1f\\ 'ENTOR. HERBERT A. PORTER gqw.

Patented Dec. 7, 1943 UNITED STATES PATENT OFFlCE This invention relates to a wedge or fastener for the purpose of securing flexible insulating tubing in the usual holes, or knock-outs of an outlet or box or the like so as to positively hold the flexible tubing in place and also to fill and close the unused portion of the hole or knockout through which the flexible tubing is inserted; the flexible tubing being of the type used around electric wiring.

Another object of this invention is to provide a flexible tubing fastener which is highly useful and simple in construction. Convenience of arrangement, lightness and comparative inexpense of manufacture are further objects which have been borne in mind in the production and development of the invention.

In manufacturing the device, while the various elements thereof may be constructed in any suitable manner and of any suitable material, yet it is preferable to form the same from sheet metal stampings on account of the cheapness, lightness and strength of the latter; but irrespective of these details in manufacturing, the essential features of the invention are always preserved.

With the foregoing and other objects in View,

which will be made manifest in the following detailed description, reference is had to the accompanying drawing for the illustrative embodiment of the invention, wherein:

Fig. l is a top plane view of my fastener.

Fig. 2 is a sectional view of my fastener.

Fig. 3 is a bottom plane view of my fastener.

Fig. 4 is an end View of my fastener.

Fig. 5 is another end view of the fastener from the opposite end.

Fig. 6 is a side view of the fastener in position, and

Fig. '7 is a sectional end view of the fastener in fastening position.

This invention particularly pertains to improvements on the type of flexible tubing fastener described in my previous Patent No. 1,530,617, granted March 24, 1925.

The flexible tubing fastener herein illustrated is preferably made of sheet metal. It has a base l5 with substantially parallel upturned sides It tapering toward an end ll of said base. These sides l6 are provided with aligned notches l8 at the highest or largest part of their taper and spaced from the straight ends IQ of said sides IS.

The end of the base it between the straight ends iii of the sides It is bent at an angle to the base so as to extend between the straight portions l9 of the sides it. The bending line of this bent end 2| is substantially opposite to the respective notches [8. This bent end 2| extends to a point slightly below the free edges of the respective sides It.

The base I5 is provided with a retaining finger 22. This finger 22 extends from the point of the base where the bent portion 2| joins the straight portion of the base l5. In the herein illustration the finger 22 is punched out of the bent portion 2| so that it leaves a hole 23 in said bent portion 2|. The finger 22 is so punched out that it is joined to the base l5 and is bent toward the outer side of the base l5 oppositely to the bent portion 2|. In other words the finger 22 is bent away from the space between the sides It. The outer surface or side of the base l5 beyond the plane of which the finger 22 projects is the side which is in engagement with the flexible tubing. The angle of projection of the finger 22 is such as to tighten the engagement between the fastener and the flexible tube so as to prevent the removal of the flexible tube from the knock-out hole unless the fastener is first removed.

In Figures 6 and '7 a fragmental portion of the box wall 24 represents the usual wall around the hole or a knock-out hole of the type used on outlet boxes, fuse or switch boxes and the like electrical equipment in to which conductor wires are to be extended from the outside. The flexible tubing 26 has the conductor wire 21 therein and is usually considerably larger in diameter than the wire 2! so that it is comparatively free to slide on the wire 27. The end of the flexible tubing 26 is inserted so that the lower ends of the ta pered sides l6 are leading the insertion of the fastener and form the point of the wedge. It is to be noted that the finger 22 projects away from the direction of insertion so that it does not hinder the insertion of the fastener in place. The wedgeis inserted until the notches I8 are in engagement with the edges of the hole 28 and extend over the wall 24 around the hole 28. This engagement will hold the fastener firmly in place and against axial movement in the hole 28. The Wedge or fastener by the engagement of its base IS with the flexible tubing 26 partly flattens the flexible tube 26. The finger 22 still further dents into the periphery of the flexible tubing 26. The wedge or fastener may be inserted from either side of the hole 23 according to the direction from which the pulling force on the flexible tubing or loom is anticipated. The finger 22 should point in a direction opposite to the expected direction of pull so as to resist pulling forces in that direction. Of course the taper engagement of the finger 22 with the flexible tubing 26 creates increased frictional force which holds the tubing in position securely and prevents its sliding relatively to the bottom of the base I5 in either direction. In wedging the fastener the forces are applied to the straight ends IQ of the sides l6 and as the tapered sides I6 enter into the hole 28 they bear against the adjacent edges of the hole 28 and compress the flexible tubing. The tubing remains under pressure even after the notches l8 snap into place over the edge of the hole 28 and thus is held in place by the fastener herein described.

I claim:

A flexible tubing fastener, comprising a base having upturned sides tapering toward one end, said sides being provided with notches between the ends of the device at the highest portions of said sides, and a finger extended from the portion of the base substantially opposite said notches and in a direction outwardly from between the sides and substantially oppositely to 10 the direction of said taper of said sides.

HERBERT A. PORTER. 

